The present invention relates generally to fire barriers and more particularly to fire barriers that are installed into floor to floor spaces created by mandated expansion joints where the installation is required to be from the undersides of the floor sections, retainers that act to support and secure the barrier to the floor so that the barrier maintains its predetermined shape, and tools for installing said bottom mounted fire barriers.
The background information discussed below is presented to better illustrate the novelty and usefulness of the present invention. This background information is not admitted prior art.
Modern building codes require that the stresses experienced by buildings from, for example extreme and/or repetitive changes in temperature, the force of high winds impinging on the building, multi-directional forces due to seismic events, settling of subsoil, building remodels, and excavation on or near the site, must be taken into account in the building design. To accommodate these stresses, buildings must now be constructed with code mandated spaces between wall, floor, and ceiling structural sections. These spaces, referred to as “expansion joints” or “expansion joint spaces” provide for differential building movement without risking damage to the whole structure.
While expansion joints improve the life-time integrity of structures, they also present major risks to the structure. In the event of fire, expansion joint spaces act as chimney flues providing pathways for gases, flame, and smoke to spread rapidly throughout the structure. To counter the flue effect, building codes for commercial structures generally require fire barriers, sometimes referred to as fire stops, to be installed in the expansion joints, as the barriers act to prevent or to reduce the rate of flames and smoke passing through the joints into adjoining areas. Fire barriers offer protection from the effects of fire to both the building and the inhabitants of the building by extending the time available for inhabitants to leave the building and for fire fighters to get to the fire.
During their lifetime, fire barriers, like buildings, undergo stress when a building is subjected to movement, whether from earthquake activity, ground settling, wind, or temperature contraction or expansion. During a fire, building joints and their associated fire barriers are likely to be subject to even greater stress than usual, making it essential that the fire barriers retain their integrity to prevent the migration of gases, flame, and smoke. Accordingly, fire barriers are legally mandated to be tested, rated, and certified. There are two currently mandated tests. One measures the ability of a fire barrier to maintain its structural integrity under compressional and tensional motion. This test is referred to as the “cycle” test and its parameters are specified by ASTM 1399. The other test is referred to as the “fire” or “burn” test and its parameters are specified by UL 2079. The two tests are conducted in sequence. A fire barrier is first cycled between forces of compression and tension 500 times and then, if the barrier passes that test, it is placed into a furnace where it is tested for its ability to resist and prevents flame, heat, and gases from passing through the barrier.
Because all buildings have walls, floors, and ceilings that create corner joints where they meet, two kinds of fire barriers are needed in order to have fire-stop protection in a building: straight-line fire barriers and multi-directional barriers. Until recently, the only fire barriers commercially available and tested were the straight-line, i.e., one dimensional fire barriers. These barriers are made to be installed between the straight segments of walls, ceilings, or floor units that are separated by the mandated expansion joint space. It is expected that straight-line fire barriers are tested and certified.
The importance of correctly installed, tested, and listed fire barrier systems in buildings is increasingly recognized by building officials, owners, insurance companies, contractors, and the public. Moreover, in order to maintain their integrity over their lifetime in a structure, the installation procedures used are also of great importance. As mentioned above, fire barriers are designed to fit into the space created by the expansion joint where the expansion joint is the space between building units, such as between two wall sections, ceiling and wall units, wall and floor units, and floor to floor units. Today, such building units are often constructed from pre-cast concrete, or the like. Pre-cast concrete typically comes in 4½ inches thickness. Thus, for example, two adjacent floor sections of pre-cast concrete provide a depth of 4½ in which to install a fire barrier. This would be difficult under any circumstances as the thickness of the barrier alone is often greater than 4½ inches. Recently, however, fire regulations require a moisture impermeable cover to be placed over the wire barrier, to protect the barrier from damage due to water or other liquids getting to the barrier, such when floors are being washed.
Moisture impermeable covers (referred to in the industry as “boots”) are about 4 inches thick. The boots cannot protrude above the floor surface as they would create tripping hazards and would expose themselves to damage. The moisture impermeable covers fill, or nearly fill, the space between the pre-cast floor units, leaving little or no room for a fire barrier or for installation of the fire barrier. Top or outer surface mount installation cannot be used because of the presence of the boot and because mounting devices and associated hardware cannot be protrude above the floor surface. The presence of the boot and the minimal thickness of the pre-cast floor sections eliminate side-mounting of the fire barrier. Thus, what is desperately needed in the art are tested and certified fire barriers that can be bottom-mounted into expansion joint spaces that are about 4½ inch thick, such is found in pre-cast building floor or other units.
To install a barrier so that it is installed tight up against the building structure means that the barrier must be kept tight to the structure until it is securely and fixedly secured. This is a challenge for workers, as barriers are often 10 feet long. What is desperately needed is a way to maintain the barrier positioned against the building structure until the barrier is securely installed.
Another recognized problem in the fire barrier industry is the danger posed to workers while installing fire barriers in expansion joint spaces in high rise buildings. The longer and/or wider a fire barrier, the greater is its weight. It is very hazardous for one, two, or even three workers to have to lift and hold in place until attached heavy fire barriers. Thus, what is also desperately needed is a way to support a barrier in an extension joint space until it is firmly attached.